The present invention relates generally to vehicle traction control systems and more particularly to a vehicle traction control system that controls the acceleration of any one of the vehicle, the vehicle driveline and the vehicle power train by comparing an actual acceleration value to a predicted maximum.
Conventional automotive vehicles are typically equipped with a power train for producing a source of rotary power and a driveline for transmitting rotary power to a set of vehicle drive wheels. While the modern power train configurations have, for the most part, proven themselves to be satisfactory for producing rotary power, several limitations have been noted. One such limitation of the modem power train configurations is their ability, on occasion, to supply too much rotary power to one or more of the vehicle drive wheels to thereby cause wheel slip which renders the vehicle somewhat more difficult to control.
Prior attempts to limit wheel slip typically employ a scheme that transfers torque from one or more of the slipping wheels to one or more of the non-slipping wheels. Although torque management schemes such as this are known to immediately reduce the magnitude by which the slipping wheel or wheels are slipping, the transfer of the excess torque to a non-slipping wheel can, at times, render the non-slipping wheels more susceptible to slip. This is particularly true when the vehicle is being operated on a surface with a relatively low coefficient of friction, such as on ice.
Accordingly, there is a need in the art for an improved traction control system and method for controlling the torque that is transmitted to the drive wheels of a vehicle.
In one preferred form, the present invention provides a method for abating wheel slip in a vehicle having a power train and a drive line. The method includes the steps of:
determining an actual angular acceleration (xcex1a) of a portion of the drive line; determining a maximum predicted acceleration (xcex1p) of the portion of the drive line; determining the existence of a wheel slip condition based on xcex1a and xcex1p; if a wheel slip condition is occurring, determining an amount of excess torque (Tx) that is being delivered to the drive line; and reducing an amount of torque that is being delivered to the drive line by an amount (Ter) that is based on the value of Tx.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.